1. Field of the Invention
The present invention relates to an excimer lamp apparatus that radiates ultra-violet light, for example, to cure resin or for surface treatment and/or surface cleaning of semiconductor wafers, glass substrates, and so on.
2. Description of Related Art
An excimer lamp that is included in an excimer lamp apparatus is described in Japanese Unexamined Patent Application Publication No. 2000-311658.
This excimer lamp is an electrodeless field-discharge excimer lamp including a discharge container containing discharge gas therein and having an outer electrode wound around the outside thereof. A highly electrically insulating tube having an inner electrode wound around the outside thereof is inserted in the discharge container substantially at the center thereof. Excimer lamp illumination is performed by electric field discharge by applying a high frequency ranging from 1 MHz to 100 MHz, to the inner electrode. The highly insulating tube has a trigger electrode and the inner electrode, which has two slit sections extending along the entire length of the tube axis.
Japanese Unexamined Patent Application Publication No. 2000-311658, paragraph [0013] discloses that an excimer lamp having such a configuration as described above will be able to start up quickly as a result of superposition effects generated by two discharges: one is the discharge formed between the trigger electrode and the outer electrode, and another is between the outer electrode and the inner electrode.
Therefore, in order to start-up quickly by generating discharge, this excimer lamp must have the trigger electrode separately from the inner electrode.
In consequence, the trigger electrode should be set facing the outer electrode, with the discharge space of the container therebetween. The inner electrode is limited in size and cannot be disposed along the entire space of the discharge container because of the space occupied by the trigger electrode and a spacing needed to avoid non-intentional discharging between the inner electrode and the trigger electrode in the adjacent slits, thus making it difficult to ensure a sufficiently large discharge region inside the discharge container.